VEHICLE WITH A HIGH-VOLTAGE STORAGE SYSTEM

Description

[0001] The present invention relates to a vehicle with a high-voltage storage device according to the preamble of patent claim 1.

[0002] From DE 10 2016 215 131 B3 an electrical accumulator is known which is arranged in a housing, wherein an intumescent adhesive tape is provided on an inner side of the housing and / or on a surface of the accumulator.

[0003] EP 2 244 318 A2 discloses a thermal management system for battery packs, consisting of a battery pack housing for accommodating multiple batteries, which housing is made of a high-temperature material. Furthermore, the thermal management system has an emergency venting port in a wall of the battery pack housing for discharging hot gas from the interior of the battery pack housing.

[0004] WO 2013 / 110406 A1 discloses a battery module comprising a housing in which at least one battery cell is arranged. The housing is completely covered with a heat-insulating layer. This advantageously protects the interior of the housing, and thus the battery cells, from the ambient temperature, allowing a stable temperature to be maintained in the interior of the battery module over an extended period.

[0005] High-voltage storage systems in electric or hybrid vehicles, such as the BMW i3, have a high-voltage storage housing with several so-called "cell modules" (hereinafter also referred to as "battery modules") arranged within it. Each of the cell modules or battery modules consists of several battery cells arranged one behind the other in a row, which are electrically interconnected. The electrical interconnection of the individual battery cells is achieved via a so-called "cell contact system." Depending on whether the battery cells of a cell module are connected in series or parallel, the cell contact system electrically connects like- or unlike-poles of the battery cells of a target module.

[0006] The individual battery cells each have a battery cell housing. An emergency vent is provided in each battery cell housing. If, for example, in an extremely serious accident, battery cells are damaged and / or a short circuit occurs in or between individual battery cells and the interior of a battery cell heats up to an unacceptable level, emergency venting of the affected battery cells must be possible. Emergency venting takes place via the emergency vent, which can be designed, for example, as a predetermined breaking point. This opens when a predetermined internal cell pressure is exceeded, allowing gas to escape from the interior of the battery cell. In extreme cases, such asIn the event of severe damage to individual battery cells, the escaping gas can ignite under very unfavorable circumstances. The escape of flames into the surrounding area or into the vehicle's passenger compartment is reliably prevented by the fact that the battery cells or cell modules are arranged in a high-voltage storage housing. The high-voltage storage housing of the aforementioned "BMW i3" is a relatively rigid aluminum housing, which is sealed "at the top," i.e., toward the passenger compartment, by a screwed-on cover.

[0007] The object of the invention is to create a vehicle with a high-voltage storage device which, compared to vehicles with conventional high-voltage storage devices, offers even greater safety with regard to possible fire hazards.

[0008] This object is achieved by the features of patent claim 1. Advantageous embodiments and further developments of the invention can be found in the subclaims.

[0009] The starting point of the invention is the consideration that in the event of extreme mechanical damage to individual battery cells and / or cell-internal short circuits, very hot, burning gas should be able to escape from the interior of individual battery cells into the interior of the high-voltage storage device via emergency venting openings in the battery cell housing.

[0010] The starting point of the invention is a vehicle with a high-voltage storage device, which has a housing (high-voltage storage device housing) and at least one cell module (hereinafter also referred to as a "battery module") arranged in the housing. The cell module or battery module, in turn, has several battery cells electrically connected to one another via a cell contact system. The individual battery cells each have a battery cell housing with an emergency venting opening that opens at a predetermined internal cell pressure. It can be provided that the cell contacting system completely or at least partially covers the emergency venting openings of the battery cells of the respective cell module. In the event of a malfunction or damage to individual battery cells, hot or burning gas can escape from the interior of the battery cell housing into the interior of the high-voltage storage device housing through the emergency venting openings.The emergency venting openings face the cell contact system and / or a wall of the housing.

[0011] The core of the invention is that the cell contacting system, preferably also the wall of the housing of the high-voltage storage device, is or are provided with a heat protection layer, in particular with a heat protection lacquer layer, at least in those areas in which the emergency venting openings are arranged. This prevents hot or burning gas escaping from one or more battery cells via the emergency venting opening(s) from directly impinging on the wall of the housing of the high-voltage storage device. Hot or burning gas therefore first impinges on the heat protection layer provided on the cell contacting system, preferably also on the heat protection layer provided in the area of the emergency venting openings on the inside of the wall of the housing of the high-voltage storage device. This ensures that even at very high temperatures of the escaping gas (e.g.Temperatures of more than 1000°C) prevent hot gas from burning through the wall of the high-voltage storage unit's housing and escaping from the high-voltage storage unit, at least for a specified period of time. This contributes to a further improvement in passenger safety in electrified vehicles. Flames escaping from the high-voltage storage unit's housing can thus be prevented with even greater reliability.

[0012] Applying a heat protection layer to the cell contact system and the inner wall of the housing of the high-voltage storage unit in the area of the emergency degassing openings is cost-effective, easy to industrialize, and involves only a very small additional weight.

[0013] The invention thus prevents direct impact on the battery wall. The term "wall" of the high-voltage storage unit's housing, or the term "battery wall," should be understood very broadly. In principle, this can refer to a bottom wall, a side wall, or an upper wall (e.g., the cover) of the high-voltage storage unit's housing.

[0014] According to a further development of the invention, the cell contacting system is arranged between the emergency degassing openings of the battery cells and the wall of the housing of the high-voltage storage device.

[0015] According to a further development of the invention, the cell contacting system comprises an electrically conductive conducting element that is electrically connected to electrodes of a plurality of battery cells. The conducting element can be, for example, a conducting sheet (e.g., steel or aluminum sheet). It can be provided that the conducting element is supported or held by a holding element. The holding element can be, for example, a plastic part (e.g., an injection-molded part). The cell contacting system within the meaning of the present invention can be formed by the conducting element and / or by the holding element. Accordingly, the heat protection layer can be applied to the conducting element and / or to the holding element.In this case, when hot or burning gas escapes from one or more battery cells, the cell contact system acts similarly to a "baffle plate", which prevents hot or burning gas from directly impacting the material of the wall of the high-voltage storage unit's housing.

[0016] According to a further development of the invention, the heat protection layer can be an intumescent layer. Intumescent materials are known from fire protection technology. When an intumescent material is exposed to a flame, the material expands or swells significantly. This results in an increase in volume of the intumescent material. The material foams or expands and becomes porous, further increasing its insulating and fire-retardant properties.

[0017] According to a further development of the invention, it can be provided that the heat protection layer provided on the cell contacting system and / or on the wall of the housing of the high-voltage storage device is a ceramic layer or a layer containing ceramic particles.

[0018] As already mentioned above, the heat protection layer can be provided only in those areas where emergency venting openings are located on the cell contact system, preferably also on the wall of the high-voltage storage unit's housing. Therefore, the entire cell contact system or the entire wall of the high-voltage storage unit's housing does not necessarily need to be provided with such a heat protection layer. Rather, a "local reinforcement" of the cell contact system or the wall of the high-voltage storage unit's housing with such a heat protection layer is sufficient.

[0019] For example, it can be provided that the heat protection layer has a layer thickness of at least 0.1 mm.

[0020] The wall of the housing of the high-voltage storage device can be made of aluminum or an aluminum sheet, which is provided with a heat protection layer at least or exclusively in the area(s) where the emergency venting openings are located. For example, it can be provided that the emergency venting openings are located on an upper side of the battery cell housing with respect to the direction of gravity, and that the heat protection layer is provided on an inner side or an underside of an upper side (cover) of the housing of the high-voltage storage device.

[0021] However, the wall of the high-voltage storage housing does not necessarily have to be made of metal or aluminum. In principle, the wall of the high-voltage storage housing can be made partially or entirely of a plastic material, which is provided with a heat-protection layer, at least in those areas where the emergency vents of the battery cells are located, preventing the wall from being exposed to hot or burning gas in extreme cases.

[0022] As already mentioned, it can be provided that the emergency venting openings are gas-tight when the battery cells are in good condition and only open or break open when a specified internal cell pressure is exceeded.

[0023] As already indicated, the heat protection layer can be provided on the side of the wall or cell contact system facing the emergency degassing openings.

[0024] According to a further development of the invention, the heat protection layer consists of a material which does not melt or does not burn at least up to a temperature of 1000°C or 1100°C or 1200°C or 1300°C or for a predetermined period of time.

[0025] For example, it can be provided that the heat protection layer is not perforated or burned by hot or burning gas escaping from the battery cells, at least for a period of 0.5 minutes and a temperature of up to 2,000°C, in particular up to a temperature of up to 1,600°C.

[0026] The invention is explained in more detail below in conjunction with the drawings. They show: Figure 1 shows a first exemplary embodiment according to the invention, in which a heat-protective coating is provided on the cell contact system; and Figure 2 shows a second exemplary embodiment, which is not part of the invention and in which a heat-protective coating is provided on an inner side of a cover of the high-voltage storage housing.

[0027] Figure 1shows a highly schematic representation of a battery cell 1, which is part of a cell module (not shown) consisting of several such battery cells. The battery cell 1 has a battery cell housing 2. In an upper area 2a of the battery cell housing 2, an emergency venting opening 2b is provided. When the battery cell 1 is in proper condition, the emergency venting opening 2b is closed. The emergency venting opening 2b only opens or breaks when a predetermined pressure is exceeded inside the battery cell housing 2. In the event of extreme mechanical damage to the battery cell housing 2 or a short circuit in the battery cell or between individual battery cells, a considerable pressure increase can occur inside the battery cell housing and the escape of hot or burning gases through the emergency venting opening 2. Hot or burning gas is in the Figure 1, 2 indicated by the reference number 3.

[0028] The battery cell 1 or the cell module (not shown in detail here) is arranged in a housing of a high-voltage storage device (not shown in detail here). Only a cover 4 of the housing of the high-voltage storage device is shown here. The cover 4 is located in an upper region of the housing of the high-voltage storage device with respect to the direction of gravity, which is indicated by an arrow 5. A cell contact system 6, shown here only very schematically, is arranged between the cover 4 and the battery cell housing 2. Individual poles (like-numbered poles or unlike-numbered poles) of individual battery cells of a cell module are electrically connected or interconnected via the cell contact system 6. The cell contact system always has a conducting element, which can be formed, for example, by a conducting plate, via which the poles of the individual battery cells of the cell module are electrically connected to one another.Additionally, the cell contacting system may include a holding element that holds or supports the conducting element, which may, for example, be made of a plastic material. Figure 1 In the exemplary embodiment shown, a heat protection varnish 7 is provided on an upper side of the cell contacting system 6, e.g., on the holding element or a cover of the cell contacting system. The heat protection varnish does not necessarily have to be provided on a side facing away from the battery cell 1 or the battery cells of the cell module. Alternatively or additionally, the heat protection varnish can also be provided on a side of the cell contacting system 6 facing the battery cell 1 or the battery cells of the cell module, i.e., on the side of the cell contacting system 6 facing the emergency venting opening 2b.

[0029] The cell contacting system 6 and in particular the heat protection layer 7 prevent, at least for a predetermined period of time, hot or burning gas 3 escaping from the emergency degassing opening 2 from directly impinging on the inside or underside of the cover 4 of the housing of the high-voltage storage unit.

[0030] The cell contact system 6 or the heat protection lacquer or heat protection layer 7 provided thereon thus acts as a type of impact layer, which significantly reduces the risk of hot or burning gas burning through the wall of the high-voltage storage housing or through the cover 4.

[0031] In the Figure 2 In the embodiment shown, the heat protection layer 7 is provided on an inner side of the wall of the housing of the high-voltage storage device or, specifically here, on an inner side or underside of the cover 4 of the housing of the high-voltage storage device.

Claims

1. Vehicle with a high-voltage storage device, which has a housing in which at least one battery module is arranged, which has several battery cells (1) electrically connected to each other via a cell contacting system (6), wherein the battery cells (1) each have a battery cell housing (2) with an emergency degassing opening (2b) that opens at a predetermined internal cell pressure, through which hot or burning gas (3) can escape from the interior of the battery cell housing (2) into the housing of the high-voltage storage device in the event of a malfunction or damage to individual battery cells (1), wherein the emergency degassing openings (2b) face the cell contacting system (6), characterized in that the cell contacting system (6) is provided with a heat protection layer (7), in particular with a heat protection coating layer (7), at least in those areas where the emergency degassing openings (2a) are arranged.

2. Vehicle according to claim 1, characterized in that the emergency degassing openings (2a) additionally face a wall (4) of the housing of the high-voltage storage device and additionally the wall (4) of the housing of the high-voltage storage device is provided with a heat protection layer (7), in particular with a heat protection coating layer (7), at least in those areas where the emergency degassing openings (2a) are arranged.

3. Vehicle according to claim 2, characterized in that the cell contacting system (6) is arranged between the emergency degassing openings (2b) and the wall (4).

4. Vehicle according to any one of claims 1 to 3, characterized in that the cell contacting system (6) has an electrically conductive conductor element electrically connected to electrodes of several battery cells (1) and / or a holding element carrying the conductor element, wherein the heat protection layer (7) is applied to the conductor element and / or to the holding element.

5. Vehicle according to any one of claims 1 to 4, characterized in that the heat protection layer (7) is an intumescent layer.

6. Vehicle according to any one of claims 1 to 5, characterized in that the heat protection layer (7) is a ceramic layer or a layer containing ceramic particles.

7. Vehicle according to any one of claims 1 to 6, characterized in that the heat protection layer (7) has a layer thickness of at least 0.1 mm.

8. Vehicle according to any one of claims 1 to 7, characterized in that the wall (4) consists of aluminum sheet which is provided with a heat protection layer (7) in the area or in those areas where the emergency degassing openings (2b) are arranged.

9. Vehicle according to any one of claims 1 to 8, characterized in that the wall (4) consists of a plastic material which is provided with a heat protection layer (7) in the area or in those areas where the emergency degassing openings (2b) are arranged.

10. Vehicle according to any one of claims 1 to 9, characterized in that the emergency degassing openings (2b) are gas-tight sealed when the battery cells (1) are in proper condition.

11. Vehicle according to any one of claims 1 to 10, characterized in that the emergency degassing openings (2b) are each formed by a predetermined breaking point that opens when a predetermined pressure inside the respective battery cell housing (2) is exceeded.

12. Vehicle according to any one of claims 1 to 11, characterized in that the battery cells (1) are arranged such that the emergency degassing openings (2b) face an upper wall (4) or a cover of the high-voltage storage device with respect to the direction (5) of gravity.

13. Vehicle according to any one of claims 1 to 12, characterized in that the heat protection layer (7) is provided on a side of the wall (4) facing the emergency degassing openings (2b).

14. Vehicle according to any one of claims 1 to 13, characterized in that the heat protection layer (7) does not melt and does not burn up to a temperature of 1,000°C or 1,100°C or 1,200°C or 1,300°C.

15. Vehicle according to any one of claims 1 to 14, characterized in that the heat protection layer (7) is not perforated and not burned by hot or burning gas escaping from the battery cells (1) for a duration of 0.5 minutes at a temperature of up to 2,000°C, in particular at a temperature of up to 1,600°C.